The present invention relates to a method for fabricating a semiconductor device, and more particularly, to a method for fabricating a cylinder type capacitor in the semiconductor device.
Although, a capacitance target area is scaled down since semiconductor devices, such as a dynamic random access memory (DRAM), become highly integrated, demanded capacitance is not decreased. Thus, various methods of forming a capacitor having a great capacitance on a small area are suggested. More particularly, a cylinder type capacitor is used for enlarging an electrode area.
FIGS. 1A to 1C illustrate cross-sectional views of a method for fabricating a typical cylinder type capacitor.
Referring to FIG. 1A, an etch stop layer 11 and an insulation layer 12 for storage nodes are successively formed over a substrate 10 having a given understructure. The insulation layer 12 and the etch stop layer 11 are selectively etched to expose a portion of the substrate 10 and thus form a trench 13 for a storage electrode region. Herein, the exposed portion of the substrate 10 may be used as a storage node contact.
Referring to FIG. 1B, a conductive layer is formed over a resultant structure including the trench 13. Thus, a storage electrode 14 is formed by performing an etch back process until the insulation layer 12 is exposed.
Referring to FIG. 1C, the insulation layer 12 is removed by using wet chemicals, leaving the cylinder type electrode 14. Then, although it is not shown, a dielectric layer and a plate electrode are successively formed over a surface of the cylinder type electrode 14 and thus, a capacitor structure is formed.
As the semiconductor devices become more highly integrated, an area of a storage electrode is also needed to be enlarged to secure sufficient capacitance. However, since there is a limitation to horizontally enlarge the area of the storage electrode, it is required to vertically enlarge the area of the storage electrode. That is, in order to enlarge the area of the storage electrode, a height of the storage electrode should be increased. In the meantime, in case of increasing a height of the cylinder type capacitor, the storage electrode may lean to a neighboring storage electrode when removing the insulation layer for storage nodes by using the wet chemicals and thus, a bridge is generated between neighboring storage electrodes due to the leaning effect. As a result, the semiconductor devices have defects.